In a wireless communication system, a power control method is used as a method for reducing a path-loss according to a distance between a base station and a user equipment and for reducing inter-cell interference due to an interference from a neighboring cell. A power control method corresponds to a method used by a wireless communication device for controlling transmission power, so that data can be transmitted at a lowest power level, while maintaining a certain quality of service (QoS) level. Most particularly, in a multi cell environment, user equipments that are located at a cell boundary region are mostly affected by path-loss, inter-cell interference, and so on. The user equipment should be capable of transmitting data by deciding an adequate transmission power level, so that the service quality can be prevented from being degraded due to path-loss, while the corresponding user equipment avoids interfering with other neighboring cells.
The conventional user equipment is equipped with only one power amplifier and is capable of only performing uplink transmission through 1 antenna port. Conversely, the conventional base station is equipped with multiple power amplifiers and is capable of performing downlink transmission through 1 antenna port or multiple antenna ports. Accordingly, in the conventional wireless communication system, a peak between uplink and downlink/asymmetry in an overall system throughput is/are considered as crucial drawbacks. Therefore, in order to enhance the uplink peak/asymmetry in the overall system throughput, it is now being considered that transmission through multiple antenna ports should also be adopted in an uplink.